Emissions has to the the answer. Though it could be Frequency range, but I doubt it.
Economic concern and stability
Explanation:
The economic problem, which is sometimes considered the basic or core economic problem, argues that the available resources of an economy are inadequate to satisfy all human needs and desires. Economics involves learning how money can be distributed under inadequate circumstances.
The avoidance of undue volatility of the macro economy ensures economic stability. The economy would be seen as economically stable with fairly constant production growth and low and stable inflation.
A source that consists of original material, such as an interview
